1. Field of the Invention
The present invention relates to reinforced concrete structures and to methods for their preparation and is more particularly concerned with the preparation of non-woven fabric reinforced concrete structures which can take the form of panels, load-bearing decks, roadbeds, walls and the like.
2. Description of the Prior Art
In my previous U.S. Pat. No. 4,159,361 there is described a reinforced panel structure which comprises a panel core formed from a cementitious composition having controlled water bleeding characteristics and having a fabric reinforcing layer disposed in the panel core adjacent to at least one surface thereof. The panel is capable of being bent, after setting, into a curved structural member without substantial loss of structural strength. The combination of materials and the mode of construction of these panels represented a marked improvement, particularly in the ability to be flexed after forming, over those previously known in the art. The relevant prior art is discussed in detail in the aforesaid U.S. Pat. No. 4,159,361, the two most closely related structures being those shown in U.S. Pat. No. 3,284,980 (Dinkel) and U.S. Pat. No. 3,466,822 (Hull et. al.). I am also aware of the recent disclosure by Bijen et al., Concrete International 1980, Fibrous Concrete, p. 194 et seq. The Construction Press, New York, of the use of fibrillated stretched polyolefin film as a reinforcing material for cement structures.
I have now found that the structural strength properties of the reinforced structures shown in the aforesaid U.S. Pat. No. 4,159,361 can be markedly improved in a manner which will be described in detail below. The modifications and improvements in the prior structures which are described herein not only relate to the preparation of cold formable panel structures disclosed in the prior art but also provide the possibility of producing load-bearing structures such as can be employed in bridge decks, highways, and the like. In addition, the structures of the present invention can be produced readily and economically on a continuous basis.